Contraction of the heart induced by the electrical excitation of myocardial cells induces ejection of blood. During this electrical excitation, the calcium concentration in the myocardial cells changes, which activates the contractile machinery in the cells, thereby inducing coordinated mechanical contraction. The heart contains a group of cells that generates an electric rhythm, the pacemaker cells at the sinoatrial node, and an excitation medium, myocardial cells, both of which contribute to generating electrical wave propagation. In the pacemaker cells, electrical excitation is generated periodically at a frequency of 60 to 100 per minute. If this excitation is propagated to the myocardial cells normally, the heart undergoes repeated contraction and expansion, supplying blood to the body.
As shown in FIG. 1, there are three kinds of arrhythmia: bradycardia, in which the electrical excitation rhythm is too slow; tachycardia, in which the electrical stimulation or conduction is too fast; and fibrillation, in which the heart rhythm is irregular and too fast. To date, no clear method has been proposed for diagnosing arrhythmias.
In most cases, doctors discover arrhythmias after their onset and then try to treat them. Currently, roughly 0.7% of the world's inhabitants suffer from arrhythmias, with 720,000 new arrhythmia patients seen annually. The cost of treating arrhythmias in the USA exceeds $18 billion and is growing. Ultimately, about 55% of cardiopaths die of arrhythmias. For the heart to eject blood normally, two conditions are necessary: first, the cardiac cells must contract synchronously, which requires that the electrical excitation of the cardiac cells occurs at essentially the same time; and second, the cardiac ventricles must relax for a sufficient period after contraction for the ventricles to fill. After contraction, very little blood remains in the ventricles. If the ventricles contract again in this state, only a small amount of blood will circulate, leading to peripheral tissue ischemia. To this end, a sufficiently long diastolic period is needed after the cardiac cells are excited electrically and contract.
There are many kinds of arrhythmia. Of these, arrhythmias attributable to an electrical wave tornado generated in the cardiac tissues are a major threat to life. In the event that an electrical wave tornado with a single center is generated and sustained in the heart, the cardiac cells are electrically excited continuously, with no relaxation. This results in rapid cardiac pulsation, which is called tachycardia. If there are several electrical wave tornados for any reason, the synchronism of the electrical excitation of the cardiac tissues is destroyed. This is fibrillation; if fibrillation is not stopped immediately, the patient may die. In brief, if fibrillation occurs, the cardiac pulsation becomes fast and the relaxation disappears, destroying the synchronized electrical excitation of the cardiac tissues. As a result, it is no longer possible for the heart to eject blood, which can lead to brain death or medical death.
Despite much research, no one has succeeded in identifying a diagnostic basis for the electrical wave tornado that is generated in the heart and the breakup of an electrical wave tornado into smaller ones. While diagnosis and examination items for diabetes, kidney disorders, coronary artery disorders, and cancers are available, there is none for diagnosing and predicting arrhythmias. In reality, a person who appears very healthy can suffer from a severe arrhythmia. That person often has an apparently normal pulse, even if the heart is heavily stressed. This means that arrhythmias such as tachycardia and fibrillation are irregular and difficult to predict.